Copper-based metal–organic framework nanoparticles for sensitive fluorescence detection of ferric ions

Abstract

A luminescent amino-functionalized metal–organic framework (Cu–MOFs) was synthesized from 2-aminoterephthalic acid and Cu(II) ions by a solvothermal method. Cu–MOFs displayed blue fluorescence with a peak at 430 nm under 330 nm excitation. Its structure was characterized by FTIR, TEM, XRD, and XPS. The fluorescence of the Cu–MOFs was quenched by Fe³⁺ in aqueous solutions. The limit of detection was 0.5 μM, and the linear working range extended from 2 μM to 35 μM. Additionally, a good logarithmic relationship between relative fluorescence intensity (F/F₀) and Fe³⁺ concentrations ranging from 2 to 180 μM was obtained with a detection limit of 1.56 μM (R² = 0.9975). No clear interference was observed when challenged with a wide variety of cations and anions. The recoveries from spiked real water samples were in the range of 91.7–107.7%, and the detection results were consistent with inductively coupled plasma mass spectrometry (ICP-MS) results. Therefore, the fluorescent sensor has great potential in environmental monitoring.